Protodeacon is an honorific rank conferred by a bishop on a deacon, almost always a married, white clergy deacon rather than a monastic one, in recognition of long or particularly distinguished service, most commonly attached to a cathedral or another prominent church where the deacon's liturgical role, especially the deacon's characteristic proclamation of the litanies and the Gospel reading, is performed with particular visibility and skill. The distinction is one of honor rather than of expanded sacramental faculty: a protodeacon performs the same rites as any other deacon, the title marking recognized seniority and service rather than conferring new liturgical functions.
The equivalent honorific for a monastic deacon is archdeacon, a title reserved for the small number of deacons who are also monks, most often serving at a patriarchal or metropolitan cathedral rather than an ordinary parish; the parallel naming, archdeacon for black clergy and protodeacon for white clergy, mirrors the broader Orthodox pattern of maintaining separate honorific ladders for the monastic and married branches of the clergy at nearly every rank.
The title protodeacon is conferred by the diocesan bishop or, for deacons attached to a patriarchal cathedral, by the patriarch himself, and carries no fixed term; it is held for the remainder of the recipient's diaconal ministry unless he is later ordained to the priesthood, at which point the diaconal rank and its honorifics are set aside in favor of the priestly ones he then begins to earn in turn.